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  <!-- 数组降维就是把多维数组变为一维数组 -->
  <!-- https://blog.csdn.net/weixin_42265852/article/details/87875913 -->
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<script>
  "use strict"; {
    {
      let arr = [[1, 2, 3], [2, 3556, 10], "我的了吧"];
      // 使用fill直接降维
    };
    {
      let entries = [1, [2, 5], [6, 7], 9];
      let flat_entries = [].concat(...entries);
    };
  };
</script>

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